Electronic devices have become slimmer in order to meet consumers' needs and desires for a smaller device for ease of use. Electronic device makers have made efforts to make electronic devices slim while increasing the rigidity thereof and improving the design. Reflecting this trend, electronic devices have been developed to efficiently place at least one antenna device that is necessarily required for communication at strategic locations within the electronic device to ensure satisfactory radiation performance.
According to one embodiment of the present disclosure, antenna devices used in electronic devices have an Inverted-F Antenna (IFA) or a monopole radiator as a basic structure, and the volume and the number of antenna radiators to be mounted may be determined according to the frequency, bandwidth, and the type of communication services that are required by the electronic device. For example, although there is a difference in frequencies used in various countries, a low band of 700 MHz to 900 MHz, a mid band of 1700 MHz to 2100 MHz, a high band of 2300 MHz to 2700 MHz are generally used as major communication bands. Additionally, various wireless communication services are used, such as BT, GPS, WIFI, etc. However, practically it is difficult to ensure that all bands are available with only a single antenna. Accordingly, in order to overcome the problem, multiple antennas are separately designed to satisfy all the aforementioned communication bands in the limited antenna volume of a given electronic device.
For example, an antenna that performs voice/data communication (GPRS, WCDMA, LTE, etc.), which may be the most important communication mode of the electronic device, may be located on the lower end portion of the device where there are fewer number of metal components that can interfere with the performance of the antenna. Based on the European standard, a total of 24 bands, including 2G (GSM850, EGSM, DCS, and PCS), WCDMA (B1, B2, B5, and B8), LTE (B1, B2, B3, B4, B5, B7, B8, B12, B17, B18, B19, B20, B26, B38, B39, B40, and B41), etc., have to be implemented. In fact, since it is difficult to satisfy service provider specifications, the specific absorption rate (SAR) standard, and to minimize effects on human bodies while implementing all the bands with a single antenna, antennas may be implemented by collecting service bands having similar frequency bands over at least two areas. By way of example, 2G (GSM850, EGSM, DCS, and PCS), WCDMA (B1, B2, B5, and B8), and LTE (B1, B2, B3, B4, B5, B8, B12, B17, B18, B19, B20, B26, and B39) may be implemented with one antenna, and LTE (B7, B38, B40, and B41) may be implemented with another antenna.
Further, in a case where the exterior of an electronic device is constituted by a metal member (e.g., a metal bezel, etc.), in order to meet the recent trend, an antenna may not be separately designed, and may be designed by making use of the metal member as an antenna radiator.
For example, in a case where a metal member arranged on the outer periphery of an electronic device is used as an antenna radiator, specific locations of the metal member are cut off by dielectric cut-off portions in order to adjust the physical length from a feeding part to the antenna, thereby enabling the antenna to operate in a desired frequency band.
However, the antenna radiator that forms the electrical length of the antenna by the cut-off portion has a problem in that the physical length from the ground part to the cut-off portion has to be modified in order to form resonance in a desired frequency band and the number of cut-off portions has to be increased in order to implement a plurality of antennas, which may cause an increased cost and spatial loss for forming the cut-off portion, as well as damage to the esthetic exterior of the electronic device.